Air cushion lift pad arrangement

ABSTRACT

An air cushion lift pad arrangement comprises a flat supporting plate having a flat flexible diaphragm sheet adjacent to it and a flat clamping plate with at least one opening therein adjacent to the diaphragm and fixed to the supporting plate. The diaphragm is also fixed centrally of the opening to the supporting plate and means are provided to introduce pressurized air into the interface between the supporting plate and the diaphragm in the uncovered area. There are perforations in the diaphragm to permit the passage of air so as to transmit a force between the inflated diaphragm and a flat surface adjacent to it.

United States Patent [151 3,692,192 Baldur 1 Sept. 19, 1972 AIR CUSHION LIFT PAD 3,513,934 5/1970 Crowley ..104/23 FS X ARRANGEMENT Primary Examiner-Gerald M. Forlenza [72] Inventor. Roman Baldur, Montreal, Canada Assistant Examiner prank E wemer [73] Assignee: Borg-Warner (Canada) Limited, Attorney-Donald W. Banner et al.

Oakville, Ontario, Canada 22 Filed: June18, 1971 [57] ABSTRACT An air cushion lift pad arrangement comprises a flat [21] Appl 154380 supporting plate having a flat flexible diaphragm sheet adjacent to it and a flat clamping plate with at least 52 us. c1. ..214/1 BE one Opening therein adjacent to the diaphragm and 511 1111. c1 ..B60v 1/00 fixed to the Supporting P The diaphragm is also [58] Field of Search ..2l4/l BE; 302/29, 31; fixed centrally of p ning o the Supporting plate 104/23 FS; 180/115, 116, 125 and means are provided to introduce pressurized air I into the interface between the supporting plate and [56] References Cited the diaphragm in the uncovered area. There are perforations in the diaphragm to permit the passage of air UNITED STATES PATENTS so as to transmit a force between the inflated 3,392,800 7/1968 Swamy ..l80/125 dlaphragm and a flat surfae adjacent 3,411,831 11/1968 Smith ..214/1 BE X 6 Claims, 6 Drawing Figures PATENTED E I 9 I 2 3.6 92. l. 92

INVENTOR. ROMAN BAL OUR BACKGROUND OF THE INVENTION One type of air cushion lift pad used at present comprises a pressure chamber defined on one side by a molded flexible diaphragm attached at its outer edge and at its center to a base plate having an air passage therethrough to supply-air under pressure to the so defined pressure chamber. The flexible diaphragm has a number of holes pierced through its surface. When air under pressure is supplied to the inside of the pressure chamber, the diaphragm becomes inflated although a small quantityof air will escape through the holes. If a relatively flat surface is placed over the inflated diaphragm, the surface will restrict the escape of air due to the small gap between the surface and the diaphragm. This will increase the pressure in the space between the surface and the diaphragm thereby permitting a certain load to be carried.

The construction of the pressure chamber and the molded diaphragm is an expensive proposition, and there are certain drawbacks in the construction. The diaphragms are generally molded of flexible rubber or rubber-like material and may include a beaded edge for connection to the base support. In any event, the par-' ticular shape of the diaphragm or assembly thereof is limited. In the event of failure of the air supply, damage of the diaphragms is likely because they, as molded parts, extend above the supporting surface.

THE INvENTIoN According to this invention an air cushion lift pad arrangement is constructed cheaply and with many advantages over the prior art constructions. All surfaces and parts are flat and therefore easy to manufacture. A supporting base block with air passages therethrough has a flat flexible sheet clamped to it by means of a flat cover plate. The cover plate is provided with openings which may be of any desired shape, i.e., circular, oval, or the like, and in any arbitrary pattern or arrangement. The flat sheet is also connected to the support plate centrally of the openings as by means of a washer and screw or bolt and perforations are provided in the exposed flexible sheet. The air passages in the support plate are placed so that air under pressure is introduced into the space between the uncovered diaphragm sheet and the support plate.

When compressed air is introduced into the airpassages the flexible sheet will be inflated at its uncovered area and look somewhat similar to the molded diaphrams. When a weight carrying surface is brought into close proximity to the inflated flexible surface, the same condition will be obtained as in the prior art type of air support cushion. Air escapes from the openings and between the diaphragm and the load. The same principle can be used to transmit a force in any direction between the support plate having the diaphragm attached to it and a flat surface adjacent to the inflated diaphragm.

One great advantage in the present construction as compared with the prior art construction, in addition to the cost of manufacture, is the situation which occurs if the air pressure should suddenly fail. When using the present construction, the flexible diaphragm relaxes to a flat surface adjacent to the support plate so that the load comes into direct contact with the flat clamping plate and can slide thereon while in the prior art, the

molded diaphragm becomes damaged when the load is slid thereover.

THE DRAWINGS FIG. 1 is a sectional view through an air cushion lift pad of prior art construction and is so identified on the drawings;

FIG. 2 is an isometric view of an air cushion lift constructed according to this invention;

FIG. 2A is a sectional view through an air cushion lift pad constructed according to this invention before air is supplied to the diaphragm;

FIG. 3 is a sectional view through an air cushion lift pad construction as in FIG. 2 with a load carrying plate thereover and showing by arrows, the escape of air from the diaphragm.

FIG. 4 is a plan view of a typical air cushion lift pad arrangement according to this invention; and

FIG. 4A is a plan view of a modified arrangement.

DETAILED DESCRIPTION In FIG. 1 of the drawings, there is illustrated, in cross-section, a typical prior art air cushion lift pad construction which comprises a base 10 attached thereto with a molded flexible diaphragm 12 at its edges and at its center to form a pressure chamber 14 to which air under pressure is supplied through an opening 16 from a suitable source 18 to inflate the diaphragm 12. Perforations 20 are provided in the diaphragm so that when a load 22 is disposed thereover, a quantity of air will escape through the openings 20 into the space 24 between the diaphragm 12 and the load 22 and spill over the edges of the diaphragm. As can be understood, in the event of a failure of the air supply, the load will drop into the diaphragm and if slid thereover can cause considerable damage and perhaps destruction thereof.

FIGS. 2, 2A, 3, 4 and 4A illustrate an air cushion lift pad arrangement constructed according to this invenpad - tion; FIG. 3 shows the air flow beneath the load by suitable arrow.

' Here there is a flat base 30 having a flat flexible diaphragm sheet 32 thereover and with a flat cover plate 34 over the diaphragm sheet. 32. The cover plate 34 is provided with one or more openings 36 the sides of which can be straight or bevel, as desired, which can be circular, oval or other shapes or a mixture of such shapes, so as to leave portions of the diaphragm sheet 32 exposed. FIG. 4 and 4A show different shaped openings 36. The assembly of base 30, diaphragm sheet 32 and cover plate 34 are connected by flat head screws 38 so as to insure a flat surface 40 and the exposed or uncovered diaphragm sheet is connected cen trally of the opening 36 to the base plate 32 by means of a washer 42 and a screw 44 which does not extend above the surface 40.

There are air supply openings 46 in the base 30 to supply air under pressure from a source 48 to the exposed diaphragm portions. The exposed diaphragm portions are provided with perforations 50 to permit air passage from the pressure chamber 52 to support a load or load carrying plate 54 in the same manner as supported in the prior art. The base plate 30 and the load carrying plate 54 may be rotated as an assembly to transmit a force in any direction.

As readily seen, the construction is relatively simple, lends itself to economical manufacture and offers advantages in the event that air pressure failure occurs, as previously stated.

1 claim:

1. An air cushion lifting pad arrangement comprising a supporting member;

a flat flexible diaphragm;

a flat clamping plate having at least one opening therein and overlying said diaphragm so as to leave an uncovered area and being connected to said supporting member;

means for attaching said diaphragm centrally of said opening to said supporting member;

means to introduce pressurized air between said supporting member and said uncovered area of said diaphragm, and

perforations in said uncovered area of said diaphragm to permit the passage of air therethrough whereby to support a force on an air cushion produced thereby.

2. An air cushion lifting pad arrangement as recited in claim 1 wherein said perforations are displaced in close proximity to said attaching means.

3. An air cushion lifting pad arrangement as recited in claim 1, wherein there are a plurality of openings in said clamping plate.

4. An air cushion lifting pad arrangement as recited in claim 3 wherein said openings are circular.

5. An air cushion lifting pad arrangement as recited in claim 3 wherein said openings are oval.

6. An air cushion lifting pad arrangement as recited in claim 3 wherein said openings are various shapes. 

1. An air cushion lifting pad arrangement comprising a supporting member; a flat flexible diaphragm; a flat clamping plate having at least one opening therein and overlying said diaphragm so as to leave an uncovered area and being connected to said supporting member; means for attaching said diaphragm centrally of said opening to said supporting member; means to introduce pressurized air between said supporting member and said uncovered area of said diaphragm, and perforations in said uncovered area of said diaphragm to permit the passage of air therethrough whereby to support a force on an air cushion produced thereby.
 2. An air cushion lifting pad arrangement as recited in claim 1 wherein said perforations are displaced in close proximity to said attaching means.
 3. An air cushion lifting pad arrangement as recited in claim 1, wherein there are a plurality of openings in said clamping plate.
 4. An air cushion lifting pad arrangement as recited in claim 3 wherein said openings are circular.
 5. An air cushion lifting pad arrangement as recited in claim 3 wherein said openings are oval.
 6. An air cushion lifting pad arrangement as recited in claim 3 wherein said openings are various shapes. 